DSMC Rarefied Flow Modeling
The CRAFT Rarefied Unsteady (CRUSE) Direct Simulation Monty Carlo (DSMC) Code represents the state of the art in rarefied flow modeling based upon decades of simulation and numerical modeling experience. CRUSE is a completely new parallel DSMC solver built from scratch with advanced physics and numerical modeling in mind. For example, beyond a total collision energy model, CRUSE also implements the advanced QKinetics chemistry for dissociation. An efficient approximate nearest neighbor algorithm is used to enhance collision pairing for more accurate collision statistics.
CRUSE can perform unsteady flow simulations using both traditional and ensemble averaging schemes for maximum accuracy. Complex geometries are easily accommodated using a robust, in-situ cell cutting algorithm, which also allows for six degree-of-motion predictions. Besides the traditional specular/diffuse/CLL/vacuum boundary conditions, CRUSE also has advanced boundary conditions for variable flux (allowing for hybrid continuum-rarefied flow coupling) and sticking (for contamination). Besides both grid coarsening and refinement, CRUSE can also perform embedded DSMC-DSMC simulations for better resolution control and computational efficiency.
Predicted 6 degree of freedom (6DOF) motion of an object subject to an impulse wave. Contours of number density are shown.
Predicted 6 degree of freedom (6DOF) motion of an object subject to an impulse wave. Contours of number density are shown.
Adapted grid for lateral jet in cross-wind (freestream flow is from bottom to top)
Extensive diagnostic information is also available to not only identify problem areas but gauge the accuracy of the simulation results. Finally, written with object-oriented programming paradigms, CRUSE is also easily modified as every function and feature can be overloaded which allows it to be coupled with other solvers (continuum radiation, etc.) through a Multi-Physics framework. In all, CRUSE is designed to meet current and future needs of any rarefied flow simulation ranging from the low densities to the micro- and nanoscales (see http://web.mit.edu/erc/spotlights/lap-all.html).